95 years ago, on this day in aviation history the Blackburn Iris I made its first flight from the factory at Brough (Yorkshire, England). The Balckburn Iris I was a three-engined bi-plane and was build according to the Specification R.14/24 of the British Air Ministry. Both wings (wood and metal construction with fabric covering) were of equal span and had ailerons on both lower and upper wings. The fuselage had a stepped V bottom that gave excellent water handling qualities. The tail was unconventional, with two horizontal tail surfaces and three fins and rudders. It was a long-range reconnaissance aircraft for the RAF, they were operated by the No. 209 Squadron. the crew of 5 consisted of
2 pilots, side by side in the cockpit in front of the wing
forward and aft gunner
fuselage gunner
Only five aircraft were built for and used by the RAF besides the single prototype
R.B.1 / Iris I Prototype, Wooden hull. Three 650 hp (485 kW) Rolls-Royce Condor III V-12 piston engines.
R.B.1A / Iris II It was found that the wooden hull of the IRIS 1 was absorbing up to several hundreds of pounds of water. To counter this the Iris II had a metal hull. Three 675 hp (503 kW) Rolls-Royce Condor IIIA V-12 piston engines.
R.B.1B / Iris III (4 built) First flight 21st of November 1929 5 Seat all-metal hull and metal wing structure, covered by fabric Three 675 hp (503 kW) Rolls-Royce Condor IIIB V-12 piston engines.
R.B.1C / Iris IV Conversion of the Iris II. Three 800 hp (600 kW) Armstrong Siddeley Leopard III radial piston engines
R.B.1D / Iris V Final variant. Three Iris Mk IIIs were fitted with 825 hp (615 kW) Rolls-Royce Buzzard IIMS piston engines
Some specifications of the Iris III:
Crew: 5
Length: 67 ft 4.75 in (20.5423 m)
Wingspan: 97 ft 0 in (29.57 m)
Height: 25 ft 6 in (7.77 m)
Wing area: 2,461 sq ft (228.6 m2)
Empty weight: 19,301 lb (8,755 kg)
Max takeoff weight: 29,489 lb (13,376 kg)
Fuel capacity: 906 imp gal (1,088 US gal; 4,119 l) in 3 tanks above each engine
Powerplant: 3 × Rolls-Royce Condor IIIB V-12 water-cooled piston engines, 675 hp (503 kW) each
Propellers: 4-bladed fixed-pitch propellers
Maximum speed: 118 mph (190 km/h, 103 kn)
Endurance: 4 hours 54 minutes
Service ceiling: 10,600 ft (3,200 m) [22]
Rate of climb: 630 ft/min (3.2 m/s)
Wing loading: 11.8 lb/sq ft (58 kg/m2)
Power/mass: 0.0699 hp/lb (0.1149 kW/kg)
Guns: 3 × .303 in (7.7 mm) Lewis guns, 1 mounted forward and two aft in open cockpits
Bombs: Up to 2,000 lb (910 kg) of bombs
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